Detection of SARS-CoV-2 in aerosols in long term care facilities and other indoor spaces with known COVID-19 outbreaks.

Coronavirus outbreaks are likely to occur in crowded and congregate indoor spaces, and their effects are most severe in vulnerable long term care facilities (LTCFs) residents. Public health officers benefit from tools that allow them to control COVID-19 outbreaks in vulnerable settings such as LTCFs, but which could be translated in the future to control other known and future virus outbreaks. This study aims to develop and test a methodology based on detection of SARS-CoV-2 in aerosol samples collected with personal pumps that could be easily implemented by public health officers. The proposed methodology was used to investigate the levels of SARS-CoV-2 in aerosol in indoor settings, mainly focusing on LTCFs, suffering COVID-19 outbreaks, or in the presence of known COVID-19 cases, and targeting the initial days after diagnosis. Aerosol samples (N = 18) were collected between November 2020 and March 2022 in Castelló (Spain) from LTCFs, merchant ships and a private home with recently infected COVID-19 cases. Sampling was performed for 24-h, onto 47 mm polytetrafluoroethylene (PTFE) and quartz filters, connected to personal pumps at 2 and 4 L/min respectively. RNA from filters was extracted and SARS-CoV-2 was determined by detection of regions N1 and N2 of the nucleocapsid gene alongside the E gene using RT-PCR technique. SARS-CoV-2 genetic material was detected in 87.5% samples. Concentrations ranged ND-19,525 gc/m3 (gene E). No genetic traces were detected in rooms from contacts that were isolated as a preventative measure. Very high levels were also measured at locations with poor ventilation. Aerosol measurement conducted with the proposed methodology provided useful information to public health officers and contributed to manage and control 12 different COVID-19 outbreaks. SARS-CoV-2 was detected in aerosol samples collected during outbreaks in congregate spaces. Indoor aerosol sampling is a useful tool in the early detection and management of COVID-19 outbreaks and supports epidemiological investigations.

Emerging Hyalomma lusitanicum: From identification to vectorial role and integrated control.

In the Mediterranean basin, the tick species Hyalomma lusitanicum Koch stands out among other species of the Hyalomma genus due to its wide distribution, and there is great concern about its potential role as a vector and/or reservoir and its continuous expansion to new areas because of climate warming and human and other animal movements. This review aims to consolidate all the information on H. lusitanicum, including taxonomy and evolution, morphological and molecular identification, life cycle, sampling methods, rearing under laboratory conditions, ecology, hosts, geographical distribution, seasonality, vector role and control methods. The availability of adequate data is extremely relevant to the development of appropriate control strategies in areas where this tick is currently distributed as well as in new areas where it could become established in the near future.

Atopic dermatitis incidence and risk factors in young adults in Castellon (Spain): A prospective cohort study.

INTRODUCTION: There are few atopic dermatitis (AD) incidence cohort studies in young adults, the etiology of this disease remains obscure, and AD risk factors in adults are not well understood. The objective of this study was to estimate AD ten-year incidence and prevalence in a cohort of adolescent aged 14-16 at inception in Castellon province in Valencia Region, Spain and describe related risk factors. MATERIAL AND METHODS: From 2002 to 2012, a population-based prospective cohort study was carried out. Questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC) were used with an additional questionnaire for related factors completed by participants and their parents, respectively, in 2002. In 2012 the same questionnaires were completed by the participants' through a telephone interview, and incidence and prevalence of AD were estimated. Directed acyclic graphs, Poisson regression and inverse probability weighted regression adjustment were used. RESULTS: The participation rate was 79.5% (1435/1805) with AD lifetime prevalence of 34.9% and AD incidence of 13.5 per 1000 person years. Females presented higher prevalence and incidence than males. After adjustment significant risk factors were being female, history of asthma or allergic rhinitis, family history of AD, history of respiratory infections, history of bronchitis, history of pneumonia, history of sinusitis, and birthplace outside Castellon province. The highest AD population attributable risks were female, 30.3%, and history of respiratory infections 15.3%. Differences with AD childhood risk factors were found. CONCLUSIONS: AD incidence in our cohort was high and several risks factors were related to AD.

Incidence of asthma in young adults from Castellon, Spain: A prospective cohort study.

BACKGROUND: The objective was to estimate the incidence of asthma in young adults from 13-15 years old to 23-25 years old, and associated factors. METHODS: In 2012, a population-based prospective cohort study was carried out in Castellon from the cohort who had participated in the International Study of Asthma and Allergy in Childhood in 1994 and 2002. A telephone survey was undertaken using the same questionnaires. A new case of asthma was defined as a participant free of the disease in 2002 who suffered asthma, was diagnosed with asthma, or took medications against asthma based on self-report from 2002 to 2012. RESULTS: The mean age of participants was 24.9±0.6 with a follow-up of 79.1%. Asthma cumulative incidence was 3.4%: 44 new cases occurred among 1280 participants. The incidence was higher in females than males with relative risk (RR)=2.02 (95% confidence interval [CI] 1.1-3.8). A significant decrease of asthma incidence density was observed (8.2 cases to 3.5 cases per 1000 person/year). Factors associated with the incidence of asthma were allergic rhinitis (RR=4.05; 95% CI 1.7-9.6), bronchitis (RR=2.13; 95% CI 1.0-4.5), mother's age at time of birth (RR=0.87; 95% CI 0.8-0.9) and a pet other than a dog or cat (RR=0.42; 95% CI 0.2-0.9). For gender, some variations in the risk factors were observed. CONCLUSIONS: A significant decrease in the incidence of asthma was observed. Several risk and protective factors were found.

Incidence of allergic rhinitis in a cohort of young adults from 13-15 years old to 23-25 years old in Castellon (Spain).

BACKGROUND: The objective of this study was to estimate the incidence of Allergic Rhinitis (AR) in young adults and its risk or protective factors. METHODS: A population-based prospective cohort study was carried out in 2012. The cohort participated in the International Study of Asthma and Allergy in Childhood in Castellon in 1994 and 2002. A telephone survey was conducted using the same questionnaires. A new case of AR was defined as the participants free of the disease in 2002, who self-reported suffering from AR or taking medications for AR in the period 2002-2012. RESULTS: Of the 1805 schoolchildren in the cohort in 2002, 1435 young adults (23-25 years old) participated (follow-up 79.1%) in 2012; 743 were female and 692 male; their mean age was 24.9±0.6 years. Two hundred new cases of AR occurred in 1259 participants free of the disease with an incidence of 17.3 per 1000 person-years, and the incidence increased from 2002 (RR=1.42; 95% CI 1.15-1.75). The risk factors of AR adjusted by age and gender were sinusitis (RR=1.77; 95% CI 1.16-2.68), atopic dermatitis (RR=1.51; 95% CI 1.11-2.06) and constant exposure to truck traffic (RR=1.88; 95% CI 1.12-3.17). For male participants, the risk factors were asthma, sinusitis and atopic dermatitis, and for females bronchitis was a risk factor and presence of older siblings a protective factor. CONCLUSIONS: An increase in AR incidence was observed. Sinusitis, atopic dermatitis and constant exposure to truck traffic were the risk factors of the AR with some differences by gender.

Vitamin D status and latent tuberculosis infection: conversion in nursing homes, Spain.

OBJECTIVE: To examine the potential association between vitamin D (VitD) deficiency and latent tuberculosis infection (LTBI) and its effect on TB infection conversion (TBIC) incidence.MATERIAL AND METHODS: We carried out a cross-sectional and prospective cohort study of nine pulmonary TB cases that occurred in 2015-2016 in five nursing homes and one mental disability institution in Castellon, Spain. QuantiFERON®-TB Gold and the tuberculin skin test were used to detect LTBI and TBIC, respectively. Serum 25-hydroxyvitamin D was measured using chemiluminescence immunoassay. Poisson regression and inverse probability weighting were used for statistical analyses.RESULTS: The study included 448 residents, 341 staff members with 48 relatives of TB cases (participation rate 82%): of these, respectively 122 (27.2%), 37 (10.9%) and 7 (14.6%) were LTBI-positive; and respectively 22 (7.7%), 10 (3.8%) and 1 (3.7%) were TBIC-positive. LTBI was not associated with VitD status. Severe VitD deficiency (SVDD; defined as VitD level < 10 ng/ml), found in 45.1% of residents, as well as VitD levels of <30 ng/ml (aRR 10.41 95% CI 1.48-73.26), were associated with increased TBIC risk (adjusted relative risk [aRR] 12.1, 95% CI 1.51-97.10), suggesting SVDD as a threshold effect. CONCLUSION: Severe VitD deficiency is a TBIC risk factor.

[Outbreak of dermatitis caused by pine processionary caterpillar (Thaumetopoea pityocampa) in schoolchildren]. / Brote epidémico de dermatitis por la oruga procesionaria del pino (Thaumetopoea pityocampa) en escolares.

BACKGROUND: To describe a dermatitis outbreak caused by exposure to pine processionary caterpillar (Thaumetopoea pityocampa ) that took place on March 15th, 2006, in schoolchildren during their stay at a rural farm holiday centre in Villahermosa del Río (Castellón). METHODS: A cross sectional epidemiological study was carried out on seventy schoolchildren, average age 10 years, and 3 teachers from Castellón. A specific questionnaire was used to be filled in by the schoolchildren. RESULTS: Six cases of dermatitis (attack rate 8.6%: 6/70) took place after children had swum in the heated farm pool and dried themselves with towels that had been left outside the heated pool enclosure, where they had come into contact with Thaumetopoea pityocampa. The cases needed medical attention, with prescription of antihistamine drugs, corticosteroids, and cold showers. The risk of dermatitis from contact with Thaumetopoea pityocampa was very high (Odds Ratio=157.2 Confidence Interval 95% 18.4-inf). Thaumetopoea pityocampa were collected near the swimming pool and Thaumetopoea pityocampa nests were observed on nearby pines. CONCLUSIONS: The presence of Thaumetopoea pityocampa near rural centres can cause outbreaks. Health education for schoolchildren and the removal of Thaumetopoea pityocampa nests near these centres are required.

[Incidence of allergic rhinitis in a cohort of schoolchildren between 1994 and 2002 in Castellón (Spain), following the ISAAC study]. / Incidencia de rinitis alérgica en escolares entre 1994 y 2002 en Castellón según el estudio ISAAC.

OBJECTIVE: To estimate the incidence of allergic rhinitis in schoolchildren in Castellón by comparing phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC), carried out in 1994 and 2002, respectively. MATERIAL AND METHODS: A cohort study was performed with 3607 schoolchildren aged 6-7 years old who participated in phase I of the ISAAC study. Of these, 1805 participated in phase III (8 years later) at the age of 14-15 years, with 1627 schoolchildren without allergic rhinitis in phase I. The cumulative incidence of allergic rhinitis was estimated. Two definitions of new cases of allergic rhinitis were used: the first was based on medical diagnosis or treatment of the disease, and the second also included symptoms of allergic rhinitis in the previous 12 months. Relative risks were calculated using Poisson regression. RESULTS: Participation was 50.0 %, and 151 new cases of allergic rhinitis according to the first definition (cumulative incidence of 9.3 % and 1.2 % per year) and 339 new cases according to the second definition (cumulative incidence of 20.8 % and 2.6 % per year) were found. No differences in incidence by gender were observed with the first definition (RR = 1.00 95 % CI 0.73-1.38) but with the second definition, the incidence was greater in girls (RR = 1.46 95 % CI 1.18-1.82). CONCLUSIONS: The cumulative incidence of allergic rhinitis according to the first definition was in the range of incidence from cohort studies of adolescents.

[Risk factors for the occurrence of sporadic Campylobacter, Salmonella and rotavirus diarrhea in preschool children]. / Factores de riesgo de los casos esporádicos de diarrea por Campylobacter, Salmonella y rotavirus en niños preescolares.

BACKGROUND: Sporadic cases of diarrhea in preschool children are highly frequent, especially those caused by rotavirus, Campylobacter and Salmonella. The aim of this study was to identify some of the factors associated with these processes. MATERIAL AND METHODS: A case-control study of hospitalized incident cases aged less than 3 years old was performed. Questionnaires were administered at admission, before the results of stool tests were known. Susceptibility, food exposure, and environmental factors were investigated. Infants aged less than 1 year were analyzed separately. RESULTS: A total of 117 patients (rotavirus in 31, Campylobacter in 228 and Salmonella in 21, negative results in 37) and 84 controls were studied. Several protective factors, such as breast feeding and prior antibiotic use, were identified. Risk factors for diarrhea were exposure to meat products (eating or environmental exposure in the kitchen), some kinds of pets, and attendance at day care. Differences were found by etiology and age. In the culture-negative group, no risk factors were identified. CONCLUSION: The problems posed by epidemiological study of this issue are discussed. The main findings in each group of cases are interpreted and proposals are made for their application in the control and prevention of these diseases.

[Geographic variation in the prevalence of asthma symptoms in Spanish children and adolescents. International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3, Spain]. / Variaciones geograficas en la prevalencia de sintomas de asma en los ninos y adolescentes espanoles. International Study of Asthma and Allergies in Childhood (ISAAC) fase III Espana.

OBJECTIVE: To analyze geographic variations in the prevalence of symptoms related to asthma in Spanish children and adolescents. POPULATION AND METHODS: In 2001 and 2002, the Spanish arm of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase 3 collected information on 28 445 children in the age bracket of 6-7 years in 10 metropolitan areas (A Coruña, Asturias, Barcelona, Bilbao, Cartagena, Castellón, Madrid, Pamplona, San Sebastián, and Valencia) and on 31 257 adolescents in the bracket 13-14 years in 11 areas (the previously named areas plus Valladolid). An asthma symptom questionnaire was filled in by parents or the adolescents themselves. Differences in symptoms between geographic areas were analyzed by fitting a logistic regression model. The relationship between symptoms and age was analyzed by linear correlation. RESULTS: The prevalence of recent wheezing (last 12 months) ranged from 7.1% to 12.9% among 6-7-year-olds and from 7.1% to 15.3% among the 13-14-year-olds. The greatest risk of recent wheezing was observed for children in A Coruña (odds ratio [OR] =1.96 in comparison with the area of lowest prevalence; 95% confidence interval [CI], 1.65-2.33) and Bilbao (OR=1.83; 95% CI, 1.54-2.18) and for adolescents in A Coruña (OR=2.38; 95% CI, 2.04-2.79) and Asturias (OR=2.37; 95% CI, 2.03-2.77). A strong correlation (r=0.72) was observed between the prevalence of recent wheezing and age in each of the geographic areas. CONCLUSIONS: Considerable geographic variation in the prevalence of asthma symptoms can be seen in Spain even among young children. Symptoms are more frequent in children and adolescents who live on the Spain s northern Atlantic coast.

[Dermatitis outbreaks caused by Pyemotes]. / Brotes de dermatitis originados por Pyemotes.

BACKGROUND: We describe three outbreaks of pyemotes dermatitis. METHODS: We undertook case-control studies and samples of several suspected materials were taken. RESULTS: There were 126 cases, with no cases admitted in hospitals. Contact which suspected vegetable materials were the only risk factor identified. Among orange picker workers risk factor was the exposure to orange trees, where Pyemotes mite was found. CONCLUSION: To our knowledge this kind of occupational risk among orange pickers has not been described before.

[Familial outbreak of pneumonia by psittacosis]. / Brote familiar de neumonía por psitacosis.

A familial outbreak (4 cases) of pneumonia by psittacosis in Vall de Uxó (Castellón) during the month of April in 1990 is described. In addition to the epidemiologic, clinical and serologic (complement fixation) studies carried out a survey and serology of 11 healthy controls (neighbors, and employees from a bird shop) were performed. The serum of a parrot recently acquired by the patients (positive at 1/8) was analyzed. The habit of petting the animal was significantly associated with the disease. The patient's response to treatment was good. The titers of antibodies versus Chlamydia psittaci were higher than those of the controls examined and the established threshold for positivity (1/36). In addition to clinical intervention the roles of epidemiology and the participation of veterinary services are fundamental to control this disease the exact prevalence of which is unknown.

[Outbreak of Salmonella enteritidis food poisoning. Potential protective effect of alcoholic beverages]. / Brote de infección alimentaria por Salmonella enteritidis. Possible efecto protector de las bebidas alcohólicas.

BACKGROUND: On may 1994, a foodborne outbreak took place in Almazora (Castellón, Spain) after a meal with 116 persons. A sanitary study was made to find out the causes and control the outbreak. SUBJECTS AND METHODS: Inspection of the setting and a case-control study were carried out. Several foods and faecal specimens of 23 patients were investigated. We also study the effect of alcohol on the occurrence of the outbreak. RESULTS: A hundred people was interviewed (86%), 58 ill persons. Salmonella enteritidis was isolated from faeces and statistically implicated food (odds ratio = 75, IC 95 = 15.6-361), a sandwich with tuna, boiled eggs and vegetables. Among adults, epidemiological analysis showed a protective effect of alcohol, adjusted for age, sex and consumption of the implicated food (p = 0.007). CONCLUSIONS: In the study of foddborne outbreaks by Salmonella enteritidis simultaneous consumption of alcoholic drinks and foods should be taken into account to explain some exposed non-cases.

[Collective scombroid fish poisoning following tuna consumption in Castellon]. / Escombrointoxicación colectiva por consumo de atún en Castellón.

BACKGROUND: To investigate and control of a collective scombroid-fish poisoning (SFP) outbreak, that took place in Castellón, Spain. METHODS: Description of the outbreak and case-control study in order to identify risk factors. Active surveillance of SFP cases, and inspection of implicated markets. Histamine determination in urine of cases and foods. RESULTS: During June 1994, 15 cases of SFP were found out, with 12 cases occurred on June, 28 and 29. Five families were affected (attack rate 68.2%). The median incubation period was 45 minutes. Disease symptoms included facial or general flushing, headache, diarrhea, nausea, abdominal pain, and peppery taste. Implicated food was fresh tuna, bought in a hypermarket of Castellón (odds ratio = 26.4, 95% confidence intervals: 1.05-666.8), adjusted by age and sex using logistic regression analysis. Four samples of urine from cases presented histamine concentration above 35 micrograms/l. Three samples of tuna consumed by cases and one sample of tuna from the hypermarket had histamine concentration above a 200 ppm. Considering the situation of risk, remaining suspected tuna was confiscated from the hypermarket. Rest unknown if the descompositions of tuna occurred in the hypermarket or during capture and distribution. CONCLUSIONS: SFP was caused by fresh tuna ingestion with epidemiologic and analytic confirmation. Determination of histamine in urine of patients could permit to confirm SFP.

[Factors associated with sporadic cases of salmonellosis in 1- to 7-year-old children. Study of cases and controls]. / Factores asociados con casos esporádicos de salmonelosis en niños de 1 a 7 años. Estudio de casos y controles.

BACKGROUND: Knowledge about salmonellosis risk factors mainly comes from foodborne outbreaks, and we know little about sporadic cases epidemiology. However most of the cases are sporadic, specially children. This study aims to find out some of determinants of these cases. METHODS: A case-control study with incident cases and controls from the same base population (laboratory diagnosed cases). Cases were children 1-7 years old, affected by diarrhea with culture stools positive to Salmonella between december 1994 and december 1995. Controls from the same source, but positive culture to Campylobacter or viruses. We study food and other environmental risk factors. Odds ratio (OR) are calculated adjusted for age, sex, and year period (cool and cold) by logistic regression. RESULTS: Eating minced meat during three days before symptoms, OR 4.07 (1.20-13.8) and OR 5.63 (1.34-23.6); pets, OR 8.27 (1.96-34.9), and antibiotics the week before symptoms, OR 4.75 (0.84-27.0) were epidemiologically associated with salmonellosis diarrhea. CONCLUSIONS: Epidemiology of salmonellosis sporadic cases in children seems different to the foodborne associated cases and is more complex. Minced meat tree days before symptoms, antibiotics the week before symptoms, and pets could be a risk for this kind of cases. Future studies must also take account of this factors.

[Food poisoning outbreak probably of viral etiology caused by Norwalk virus]. / Brote de toxiinfección alimentaria de probable etiología vírica por virus Norwalk.

In May 1989, a foodborne outbreak of acute gastroenteritis was identified in a state school in Adzaneta, Castellón. A dtudy was undertaken to describe it, investigate its causes, and recommend adequate control measures. Sixteen children and 2 teachers were affected (attack rate: 28.57%). Kaplan and cols clinical and epidemiological criteria for Norwalk-like virus as the responsible agent were present. The probable origin of the outbreak was a foodhandler who was already ill beforehand. The examination of stools of the foodhandler and a patient showed small round structures similar to the Norwalk virus. In Spain, the number of foodborne outbreaks without known causal agent has steadily increased in recent years. It may be that this microorganism is responsible for some of these outbreaks in which, for several reasons, the causal agent cannot be identified.

[The short-term effects of air pollution on mortality: the results of the EMECAM project in Castellón, 1991-95. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad]. / Efectos a corto plazo de la contaminación atmosférica sobre la mortalidad: resultados del proyecto EMECAM en Castellón, 1991-95.

BACKGROUND: In the last decade several studies have found out an association between air pollution and mortality in levels below the standards allowed by regulations. Castellón is a small city (134,000 inhabitants) with low air pollution levels. This work aims to identify if there is a short term relation between these both variables in this city. METHODS: We used mortality data and air pollution data (black smoke and sulphur dioxide), from 1.991 to 1.995, doing an ecological study using a time series analysis with the day as unit of the analysis. Poisson regression allow us to get the relative risk adjusted by others variables (meteorological, trend, influenza, day of the week, season) in autoregresive models. RESULTS: Black smoke and SO2 daily means were respectively 34.6 and 15.7 micrograms/m3. Results showed a 3.6% (IC95 0.3-7.0) of SO2 and 3.5% (IC95% 0.5-6.5) increment of cardiovascular mortality for an increment of 10 micrograms/m3 of SO2 and black smoke respectively. Sulphur dioxide was positively associated with all four groups of mortality causes but only in cold season. CONCLUSION: Even in a small city with low air pollution levels, we found an association between air pollution and immediate mortality. In some cases, the analysis by periods (warm and cold) show an strong effect modification.

[The EMECAM project: the Spanish Multicenter Study on the Relationship between Air Pollution and Mortality. The background, participants, objectives and methodology]. / El proyecto EMECAM: Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad. Antecedentes, participantes, objetivos y métodología.

In recent years, a growing number of studies suggests that increases in air pollution levels may have short-term impact on human health, even at pollution levels similar to or lower than those which have been considered to be safe to date. The different methodological approaches and the varying analysis techniques employed have made it difficult to make a direct comparison among all of the findings, preventing any clear conclusions from being drawn. This has led to multicenter projects such as the APHEA (Short-Term Impact of Air Pollution on Health. A European Approach) within a European Scope. The EMECAM Project falls within the context of the aforesaid multicenter studies and has a wide-ranging projection nationwide within Spain. Fourteen (14) cities throughout Spain were included in this Project (Barcelona, Metropolitan Area of Bilbao, Cartagena, Castellón, Gijón, Huelva, Madrid, Pamplona, Seville, Oviedo, Valencia, Vigo, Vitoria and Saragossa) representing different sociodemographic, climate and environmental situations, adding up to a total of nearly nine million inhabitants. The objective of the EMECAM project is that to asses the short-term impact of air pollution throughout all of the participating cities on the mortality for all causes, on the population and on individuals over age 70, for respiratory and cardiovascular design causes. For this purpose, with an ecological, the time series data analyzed taking the daily deaths, pollutants, temperature data and other factors taken from records kept by public institutions. The period of time throughout which this study was conducted, although not exactly the same for all of the cities involved, runs in all cases from 1990 to 1996. The degree of relationship measured by means of an autoregressive Poisson regression. In the future, the results of each city will be combined by means of a meta-analysis.

[The EMECAM project: a discussion of the results in the participating cities. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad]. / El proyecto EMECAM: discusión de los resultados en las ciudades participantes.

This article draws a comparison and provides a discussion of the findings resulting from the local analyses of the 14 cities participating in the EMECAM Project. An analysis is made of the time series related to mortality, pollutants (particles in suspension, SO2, NO2, O3 and CO), temperature and other factors taken from records of public institutions. By using Poisson autoregressive regression, an estimate has been made of the short-term relationship between the number of deaths and the air pollution indicators in each one of the following cities: Barcelona, metropolitan area of Bilbao, Cartagena, Castellón, Gijón, Huelva, Madrid, Pamplona, Seville, Oviedo, Valencia, Vigo, Vitoria and Saragossa. The findings reveal the air pollution figures in our country to be similar to those of other European cities. The levels of the different pollutants point toward road traffic as being the main source of most of this pollution. A relationship has been found between the mortality and different pollutants in most cities, although the results are not homogeneous among the cities and show variability in the different causes under study. In some cities, especially in those having smaller populations, there have been no findings providing any evidence of a relationship, or the findings themselves are not highly consistent. The meta-analysis will provide estimates for all of the cities as a whole and will allow the possibility of making a more clear-cut assessment of the time lag impact of air pollution on the mortality. Worthy of special mention is the participation in this project of public health officers as actively involved researchers.